The present invention relates to continuous casting and more particularly to improvements in the withdrawing of an ingot as emerging from a straight or curved mold, veering the ingot towards a horizontal direction and straightening the ingot before it is moved into the horizontal direction for further processing.
Machines for continuous casting of steel, for example, are usually provided with roll tracks being disposed underneath the mold for withdrawing the ingot from the bottom of the mold and guiding the ingot along a curved withdrawl path. The ingot is usually guided here by means of rigidly mounted support rolls of the track arranged along the outer guiding path, while guiding and support rolls on the inside of the curved track are hydraulically or otherwise resiliently mounted, singly or in groups. This movability of the inside rolls serves for adjustment of the machine to different thicknesses of the ingot. Also, the ingot blank or stool for starting the machine may differ in its dimensions relative to the ingot that follows. These inner guide and support rolls are usually movable in the direction towards the radial center of the curved ingot path. As stated, the outer guide rolls are fixed with regard to their position in relation to the ingot path as such. It has to be observed here that these outer rolls may cause also some bending of the ingot into the curved portion of the withdrawal path.
These known machines have the drawback that particularly in the beginning and towards the end of a casting run the outer guide rolls are overloaded. This is true generally and noticeable particularly, if the radius of curvature is changed to bend the ingot in steps. Overloading is specifically the result of the fact that the beginning and the end portions of the ingot are relatively cool, and bending exerts considerably forces on any rigidly mounted guide roll. This is also true with regard to rolls which straighten the ingot, when it leaves the curved withdrawal path or when entering a track portion of a lesser curvature. Tests have shown that several guide rolls are overloaded by bending and straightening of about 0.3 to half a meter of the first or beginning portion of the ingot and by about half a meter length of the end portion thereof. As a consequence, these overloaded guide rolls wear very rapidly and are often damaged fairly soon following first use.